Fluids are hereby defined to be any material that is non-solid in its natural condition or materials that may be converted to and maintained in a non-solid state. Some fluid distribution systems, such as for the distribution of potable water, have been used for over one hundred years. Such systems comprise a fluid source such as a well or filtration plant, a main or distribution line connected to the source and smaller lateral lines connecting the main line to users. The main line can range in size from four inches in diameter to thirty inches or more in diameter. The main line can also be formed from a variety of materials such as iron, steel, cement or polymer. Often, a new lateral line will be required to supply a new user. It is desirable to connect the new lateral line to the main line without shutting off fluid flow to other users connected to the main line.
To fluidly connect the new lateral line to the main line without shutting off fluid flow in the main line a tapping sleeve can be used. A tapping sleeve comprises two mating saddles that are oppessedly mounted over the pipeline. A gasket is disposed between one or both saddles and the pipeline. One of the saddle sections includes a radially projecting standoff terminating in a distal flange.
In use, one set of two saddles and a gasket is secured over the pipeline where connection with the new lateral line is desired. When the saddles are fastened the gasket is clamped between the pipe and the saddles, providing a fluid seal. A valve is secured to the saddle flange. A drilling apparatus is secured to the valve. The drilling apparatus is used to drill through the pipe, after which the drill is retracted and the valve is closed. The drilling apparatus is removed. The new lateral line is fluidly connected to the valve. When the valve is opened fluid is supplied to the new lateral line and the new user.
The valve is left secured to the tapping sleeve flange during use. Thus, there is no provision to fluidly seal the tapping sleeve flange apart from use of the secured valve.
In some instances, a distribution pipeline must be relocated. In other instances the distribution pipeline will break requiring repair. Often such work must be conducted quickly to return the distribution pipeline back into service. However, there may be no valve suitably positioned to turn off fluid flow in the main pipeline to allow the work to be conducted. In other cases it may not be possible to turn off fluid flow to the damaged section of pipeline without also turning off the flow to a critical user such as a hospital. In these cases a “line stop fitting” and system can be used. The line stop fitting comprises two mating saddles that are oppessedly mounted over the pipeline adjacent the section that has broken or that needs to be moved. A gasket is disposed between one or both saddles and the pipeline. One of the saddle sections includes a radially projecting standoff terminating in a distal flange.
In use, a first set of two saddles and a gasket is secured over the main pipeline adjacent one side of the broken section. A second set of two saddles and a gasket is secured over the main pipeline adjacent the opposing side of the broken section. When the saddles are fastened the gasket is clamped between the pipe and the saddles, providing a fluid seal. A valve is secured to each saddle flange. In some variations a temporary pipe connects the valves to allow fluid flow around the broken section. A drilling apparatus is secured to each valve. The drilling apparatus is used to drill through the pipe, after which the drill is retracted and the valve is closed. The drilling apparatus is removed and a line stop apparatus is secured to each valve. The line stop apparatus comprises an expandable head on a movable ram. The valve is opened and a head of the line stop apparatus is forced into the interior of the pipe. Expansion of the line stop head into the interior of the pipe prevents fluid from moving past the head, stopping fluid flow in the main pipeline only immediately adjacent the broken section. With fluid flow stopped by the line stop head repairs can be made.
After repairs have been made to the main pipeline, the line stop heads are retracted allowing fluid communication through the repaired pipe. The valves are closed and the line stop head is removed. A completion plug is placed into the line stop apparatus. The valves are opened and the completion plug is received into, and engaged with, the interior of line stop fitting flange. Typically, the completion plug is threadedly engaged with threads in the interior of the line stop flange or set screws within the saddle flange rim are engaged into a recess in the completion plug periphery. When the completion plug is received into, and engaged with, the line stop fitting flange fluid flow through the saddle flange is prevented. The line stop apparatus is removed, the valve is removed and a blind flange and seal is placed over the top of the saddle flange.
Once the repair has been made there is usually no need to return to the repair site. Thus it is undesirable to leave the two valves, which can cost hundreds to thousands of dollars each, on the line stop flange. Hence the use of a relatively inexpensive completion plug and blind flange for sealing the line stop fitting.
While somewhat similar in appearance, a tapping sleeve and a line stop fitting can not be interchanged. The tapping fitting does not have provisions for use with a completion plug. Further, each manufacturer designs their line stop apparatus to work with their own respective line stop fitting. Thus, a line stop fitting from one manufacturer may not be compatible with a line stop apparatus from another manufacturer. To ensure quick repairs to essential distribution pipelines a maintenance department must stock a tapping sleeve for each pipeline size used in the fluid distribution network as well as a line stop fitting for each pipeline size used in the fluid distribution network. Since each line stop fitting can cost hundreds or thousands of dollars this double stocking requires a significant budget as well as room to store both the large tapping sleeves and the large line stop fittings.